Recoil mechanisms having a recoil spring disposed on a rod retained thereon by collars or flanges disposed on opposite ends of the rod are disclosed in U.S. Pat. Nos. 2,139,203 and 5,050,480. Patent '203 discloses a guide rod having flanges at both ends of the rod which are attached thereto by tapered pins. Patent '480 discloses a guide rod with an enlarged end followed by a washer to form a collar and at the other end of the rod, a flange is secured thereto by a tapered pin with an inner and an outer drive spring disposed between the flange and the collar. Each of these recoil mechanisms requires the use of a number of parts and a plurality of manipulations in assembly thereof that makes the assembly process relatively time consuming and costly.
A semi-automatic pistol manufactured by Glock, Inc. has a recoil mechanism having a guide rod and a flange button molded of a polymeric material. The guide rod has a flange at one end thereof and an axial bore that extends over the full length of the rod and includes an interlocking recess at the other end thereof. A separate fitting that includes a flange at one end thereof and an axially extending male coupling adapted to fit into the bore of the guide rod and interlock with a protrusion therein. To assemble the recoil mechanism, the recoil spring is axially fitted onto the rod and then the male coupling is urged into the bore of the rod at the other end thereof and which interlocks with the protrusion therein.
The guide rod used in the Glock has a number of drawbacks. First, the rod is difficult to mold due to the length of the through-bore. In addition, the rod must also be fabricated to have sufficient resilience to yield radially upon insertion of the male coupling of the fitting into the bore past the protrusion therein which is radially yieldable and has sufficient resilience to fully return to its original shape so as to lock the fitting therein. Because of such resilience, the rod has a tendency to be deflected or bowed and during operation is subjected to uneven wear which may result in reducing the life of the recoil mechanism.